Charleston Model Yacht Club

DF95 Tips

TRIMMING NOTES - Phil Burgess

 Camber

  • More camber equals more power. Fuller sails need to be sheeted in more to enable higher pointing.
  • Less camber allows higher pointing
  • Best to trim for more power in the main. Too much if backwinding when fully sheeted in so reduce camber.
  • Backwinding caused by main camber too large, main sheeted too far out, jib sheeted too far in


Balance

  • Boats rounds up into wind: power up jib or depower main
  • Boat heads down or has no feel: depower jib or power up main
  • Mast rake back equals power aft, rake forward equals power forward
  • More air (upwash) will be created around the jib, if the sails are set as close to one another as practical. Being close, less air will leak through the slot. The increased upwash, in turn, increases the air speed on the lee side of the sails and the efficiency of both sails is improved!


Twist

  • Nominal jib twist: upper and lower telltales flutter in unison
  • Too much jib twist: top part of jib luffs first
  • Too little jib twist: bottom part of jib luffs first
  • Reducing twist increases power, increasing twist reduces power
  • Tensioning the backstay quickly increases twist and decreases power
  • Jibs need more twist than mains. More upwash requires more twist.  Very slight over twist set in each sail is preferred.


Light air

  • Main has deep foot camber and minimum twist.  Setting a more camber forward jib (tensioning the jib luff to either move draft forward, or at least preventing it from moving aft) in conjunction with lower forestay tension is similar to changing the entry angle on the wing. This jib trim, combined with a deeply cambered (eased outhaul) fully sheeted in main with draft more forward


Heavy air

  • Flatter sails with the main trimmed closer to the rail. The forestay and jib luff has max. tension and the main is set draft aft and has been twisted to open the leech and minimize drag.


Tactics

  • Lift is a wind shift that allows a boat to sail closer to the mark
  • Header is a wind shift that forces a boat to sail further from the mark
  • Skippers that sail into a header will win most races
  • Always sail to the new wind
  • Tack only when there is a reason to do so
  • Fluky conditions mean stay close to the rhumb line
  • Always sail to the close end of the finish line
  • Ease sails when rounding the weather mark
  • Sheet in at the leeward mark
  • Take small bites going to windward to be closer to the mark​



Rudder Servo guide – Provided Courtesy of Phil Burgess

Tuning guide – Provided Courtesy of Phil Burgess

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